In this presentation i have tried to give brief explanation about the General prescribing guidelines for pediatrics, geriatrics and pregnancy.

1. General prescribing guidelines for
Pregnancy(Geriatric Population )Paediatric Population
By: Dr. Ankit Gaur
Pharm.D, M.Sc, RPh

2. General Prescribing
Guidelines for Pediatric Population

3. Introduction
• Better understanding of various physiological variables that
are regulating the fate of the drug is important to improve
both safety and efficacy of drug therapy
• Pediatric patients show such physiological variability and so it
is important to select an appropriate dose for a pediatric
patient
• Here, the organs are not matured
• The development of organs continue until at least to the age of
12 years
• Pediatric patients were always considered in the past for
treatment as MINI ADULTS

4. Introduction…
• Classification of pediatric patients:
 Preterm Neonate (Preterm Newborn Infant) (<37 weeksPreterm Neonate (Preterm Newborn Infant) (<37 weeks
gestation)gestation)
 Neonate (Newborn Infant ) (Birth To 27 Days)Neonate (Newborn Infant ) (Birth To 27 Days)
 Infant & Toddlers (28 Days To 23 Months)Infant & Toddlers (28 Days To 23 Months)
 Young Child (2 To 5 Years)Young Child (2 To 5 Years)
 Older Child (6 To 11 Years)Older Child (6 To 11 Years)
 Adolescent (12 To 18 Years)Adolescent (12 To 18 Years)
 The Adult (>18 Years)The Adult (>18 Years)

5. Premature neonate
(<37 weeks)(<37 weeks)
Neonate (Birth To
27 Days)
Infant and Toddler
(28 Days To 23
Months)
Young Child
(2 To 5 Years)
Older Child
(6 To 11 Years)
Adolescent/Teen
(12 To 18 Years)
The Adult
(>18 Years)

6. Introduction…
• Children and adults respond to drugs differently.
• There are important differences in the ADME of medications
during infancy and childhood.
• Children's body systems are less developed; their GI transit time
varies; and their body composition changes with development.
• Prescription writing must be appropriate, legible, and meticulous.
• Family education about medications and administration
techniques is an essential part of the clinician's role

7. • Promotion of safe administration of medication to children can be
enhanced by expanding pharmacokinetics in pediatric practice.
• The absorption, distribution, metabolism and excretion of
medications vary with the developmental changes that accompany a
child's growth.
• Application of paediatric pharmacokinetics to nursing practice when
administering medications to children promotes safety in practice.
• Paediatric prescribing is much more complicated than prescribing
for adults.
Introduction…

8. Physiologic
Variable
Age Group PK Result Example
↑ gastric pH Neonates, Infants,
Young Children
↑ BA of basic drugs and
acid labile drugs
↓ BA of acidic drugs
Ampicillin,
Penicillin G
Phenobarbital
(acidic)
↓ gastric and
intestinal motility
Neonates, Infants Unpredictable BA Digoxin
↑gastric and
intestinal motility
Older Infants,
Children
Unpredictable BA Digoxin
↓bile acid
production
Neonates ↓ BA Vitamin E,
Vitamin K
Bacterial Flora Neonates and
Infants
↑ BA Digoxin
Age Dependent Physiologic Variables Influencing Oral
Drug Absorption as Compared to Adults
8

9. Summary Of Drug Absorption
In Pediatric Patients
Physiologic
Variables
Neonate Infants Children
Gastric emptying time
Gastric pH
Intestinal motility
Intestinal surface area
Muscular blood flow
Irregular
>5
Reduced
Reduced
Reduced
Increased
4 to 2
Increased
Near adult
Increased
Slightly increased
Normal (2-3)
Slightly increased
Adult pattern
Adult pattern

10. Possible Pharmacokinetic Consequences
CriteriaCriteria Neonate Infants Children
Oral absorption
IM absorption
Percutaneous
absorption
Rectal
absorption
Erratic or
reduced
variable
Increased
Very efficient
↑ rate
Increased
Increased
Efficient
Near adult pattern
Adult pattern
Near Adult pattern
Near adult pattern

11. Relative GI Absorption of Selected Drugs in
Infants and Adults
11

12. Principles of
Pediatric Pharmacotherapy
• Children are not just “Little Adults”.
• Pharmacokinetic and dynamic differences led to several
disastrous situations.
• Variations in absorption of medications from different
sites (GI, IM, Skin).
• Weight and surface area may change significantly in
relatively short period
• Drug selection, doses and dosage intervals change
through out childhood (DTM essential).
• Special methods of drug administration required for
infants and young children.

13. When parents ask for antibiotics to treat viral infections:
•Explain that unnecessary antibiotics can be harmful.
– Tell parents that based on the latest evidence,
unnecessary antibiotics CAN be harmful, by promoting
resistant organisms in their child and the community.
•Share the facts.
– Explain that bacterial infections can be cured by
antibiotics, but viral infections never are.
– Explain that treating viral infections with antibiotics to
prevent bacterial infections does not work.

14. • Build cooperation and trust.
• Convey a sense of partnership and don’t dismiss the illness as “only a
viral infection”.
• Encourage active management of the illness. Explicitly plan treatment
of symptoms with parents.
• Describe the expected normal time course of the illness and tell
parents to come back if the symptoms persist or worsen.
• Be confident with the recommendation to use alternative treatments.
Prescribe analgesics and decongestants, if appropriate.
• Emphasize the importance of adequate nutrition and hydration.
• Consider providing “care packages” with non antibiotic therapies.
• Create an office environment to promote the reduction in antibiotic
use.
• Talk about antibiotic use at 4 and 12 month well child visits.

15. Drug Prescribing
In
Elderly Patients

16. • Advancing age is accompanied by pharmacokinetic and
pharmacodynamic changes which, together with impairment of
homeostatic mechanisms and the effect of coexisting disease,
contribute to a significant increase in sensitivity to particular drugs
and a corresponding increase in the incidence of adverse drug
reactions (ADRs).
• Increasing medical awareness of these facts has not universally
been translated into clinical practice as polypharmacy remains a
particular problem amongst elderly people and the degree of
polypharmacy increases with advancing age.
• Such prescribing practice serves to further elevate the risk of drug
interactions and ADRs, both directly via the synergistic or
antagonistic actions of coprescribed drugs, and indirectly by
increasing the likelihood of failed compliance.

17. INTRODUCTION…INTRODUCTION…
SPECIAL CONSIDERATIONS OF THE ELDERLY AS UNIQUESPECIAL CONSIDERATIONS OF THE ELDERLY AS UNIQUE
GROUP WITHIN THE POPULATIONGROUP WITHIN THE POPULATION
CONSIDERATION CHARACTERISTICS
Population The elderly (i.e., those older than age 65) currently
represent about 10 % of Indian population
Health The elderly experience a great incidence of
disease, physical impairments and physiological
disorders than do younger adults
Institutionalization The elderly occupy a greater share of hospital beds
(≈ 33%) and long term care facilities than do
younger adults
Drug use The elderly consume more drugs (≈ 25% of total
use) per capita than do younger adults
Drug effects The elderly experience a greater incidence of
adverse drug effects and drug-drug interactions
than do younger adults
17

18. ABSORPTION
•↓ in gastric acid secretion, GI blood flow, pancreatic trypsin, GI
motility and number of absorbing cells → altered dissolution rate ,
possible decrease in absorption rate, long time for onset on effect
of drug
•Vitamin, mineral and nutrient deficiencies common due to active
absorption of these compounds
•Drugs mostly absorbed passively
•Active absorption is affected

19. DISTRIBUTIONDISTRIBUTION
•Reduction in
– Lean body mass
– Total body water
– Plasma albumin
•Total protein concentration remains same
•Increase in body fat leading to increase in Vd of lipid soluble drugs and
decrease in Vd of hydrophilic drugs
•Delayed onset followed by accumulation and overdosing in multiple
dosing situations
•Increase in free fraction of highly bound acidic drugs and possible
decrease in free fraction of basic drugs
•Theophylline, Warfarin, Phenytoin, Diazepam, Barbiturates show
increase in t1/2

20. METABOLISMMETABOLISM
•Decrease in hepatic cell mass (28 % and 44 % in men and women by the
age of 91)
•Decrease in hepatic blood flow for about 35 %
•Possible decrease in enzyme inducibility, Acetylation, Glucuronidation
•Apparently decreased metabolism and clearance of certain drugs
(Propranolol, Labetalol, Verapamil, Metoclopramide, Opioids, Diazepam)
•Other factors like, smoking, alcohol, disease conditions, co administered
drugs like erythromycin can inhibit the metabolism still further

21. EXCRETIONEXCRETION
•When compared to 10 years, at the age of 40 years GFR reduced by 10%
and 6-10% is reduced in every 10 years after this age
•At the age of 90 years about 30-40% reduction in GFR occur
•↓ in renal plasma flow and active secretion
•↓ in excretion of renally cleared drugs (Digoxin, Penicillin, Vancomycin,
Lithium, Amino glycosides)
•Coexisting diseases like HT, DM include renal compromise
•Creatinine Clearance (ml/min)
For male = 140 – age(years) x Weight(Kg) / 72 x Serum Cr (mg/dL)
For female = 140 – age(years) x Weight(Kg) / 85 x Serum Cr (mg/dL)

22. PHARMACODYNAMICSPHARMACODYNAMICS
•Change in receptor binding decrease in number of
receptors or mechanisms
•Changes in CNS enzyme activity
•Reduction in baroreceptor reflex sensitivity
•↓ receptor response (β – adrenergic agonists blockers)
•↑ receptor response (Morphine, Diazepam)

23. SUMMARY OF PHYSIOLOGIC AND PATHOLOGIC CHANGES AND THEIR
PK AND THERAPEUTIC CONSEQUENCES IN THE GERIATRIC PATIENTS
ParameterParameter Physiologic OrPhysiologic Or
Pathologic ChangePathologic Change
OrganOrgan
ConsequencesConsequences
PKPK
ConsequencesConsequences
TherapeuticTherapeutic
ConsequencesConsequences
BodyBody
weightweight
GenerallyGenerally ↓↓eded
,,
including vital organsincluding vital organs
Loss of fluid,Loss of fluid,
↓↓eded
heart,heart,
kidney andkidney and
muscle tissue,muscle tissue,
atrophic tissueatrophic tissue
↑↑eded
blood levels,blood levels,
↑↑eded
drug conc. –drug conc. –
receptor ratioreceptor ratio
Overdosing,Overdosing,
↑↑eded
side effectsside effects
andand
toxic effectstoxic effects
GI-GI-
secretion,secretion,
GI-tractGI-tract
↓↓eded
Secretion,Secretion,
↓↓eded
GI – motilityGI – motility
↓↓eded
Blood flowBlood flow
↑↑eded
gastric pH,gastric pH,
delayeddelayed
stomachstomach
emptying,emptying,
↓↓eded
mixing ofmixing of
gastricgastric
contentscontents
AlteredAltered
dissolution rate ofdissolution rate of
Tab, Cap, delayedTab, Cap, delayed
transition to smalltransition to small
intestine,intestine,
Prolonged Ab.Prolonged Ab.
raterate
↑↑eded
time for onsettime for onset
on effect, loweron effect, lower
intensity ofintensity of
effect, ↑effect, ↑eded
duration ofduration of
effecteffect
Body fluidBody fluid TBF and ICF reducedTBF and ICF reduced HypokalemiaHypokalemia
andand
HypernatremiaHypernatremia
↓↓eded
Vd, ↑Vd, ↑eded
bloodblood
levelslevels
Overdosing,Overdosing,
increased sideincreased side
effects and toxiceffects and toxic
effects,effects,
dehydrationdehydration

24. ParameterParameter Physiologic OrPhysiologic Or
PathologicPathologic
ChangeChange
OrganOrgan
ConsequencesConsequences
PKPK
ConsequencesConsequences
TherapeuticTherapeutic
ConsequencesConsequences
Heart andHeart and
blood flowblood flow
↓↓eded
cardiac out put,cardiac out put,
↓↓eded
vascular elasticityvascular elasticity
and permeability,and permeability,
↓↓eded
blood flowblood flow
Possible venousPossible venous
congestion andcongestion and
arterialarterial
hypovolemiahypovolemia
Slower Ab. RateSlower Ab. Rate
from GI tract,from GI tract,
muscle, skin,muscle, skin,
rectum, delayedrectum, delayed
distribution;distribution;
↓↓ed Vd, ↑ed blooded Vd, ↑ed blood
levelslevels
Longer time forLonger time for
onset,onset,
overdosing,overdosing,
↑↑ed side effectsed side effects
andand
toxic effectstoxic effects
BodyBody
compositioncomposition
↓↓ed lean body mass,ed lean body mass,
↑ed fat tissue↑ed fat tissue
Organ functionOrgan function
changedchanged
↓↓ed Vd in general ,ed Vd in general ,
storage of drugsstorage of drugs
with high lipidwith high lipid
solubility in fatsolubility in fat
depots, and slowerdepots, and slower
eliminationelimination
Overdosing,Overdosing,
↑↑ed side effects,ed side effects,
↓ed response for↓ed response for
drugs of highdrugs of high
lipid solubility,lipid solubility,
hangoverhangover
phenomenon,phenomenon,
delayed onsetdelayed onset
followed byfollowed by
accumulation andaccumulation and
overdosing inoverdosing in
multiple dosingmultiple dosing

25. Parameter Physiologic Or
Pathologic
Change
Organ
Consequences
PK
Consequences
Therapeutic
Consequences
KidneyKidney ↓↓eded
renal bloodrenal blood
flow,flow,
↓↓eded
GFR andGFR and
active secretionactive secretion
↓↓eded
CreatinineCreatinine
clearance,clearance,
↓↓eded
renalrenal
functionfunction
↑↑eded
eliminationelimination
half life ofhalf life of
drugs excreteddrugs excreted
by kidneyby kidney
Over dosing, longerOver dosing, longer
duration of effect,duration of effect,
↑↑eded
side effects andside effects and
toxic effectstoxic effects
PlasmaPlasma
proteinsproteins
↓↓eded
albuminalbumin HypoHypo
albuminemiaalbuminemia
Saturation ofSaturation of
protein bindingprotein binding
and increasedand increased
concentration ofconcentration of
free drug,free drug,
shorter half-lifeshorter half-life
if highly boundif highly bound
↑↑eded
intensity ofintensity of
effect, ↑effect, ↑eded
sideside
effects and toxiceffects and toxic
effects, overdosingeffects, overdosing
HomeostasisHomeostasis Abnormal abilityAbnormal ability RestrictedRestricted
range ofrange of
regulatoryregulatory
functionsfunctions
Possible changePossible change
in Vdin Vd
Paradoxic drugParadoxic drug
reactionreaction

26. At the time of Admission:
• Review all medications (include relevant OTC, herbal,
vitamins, etc.) taken by patient
• Assess previous compliance.
• Avoid unnecessary polypharmacy by: Using drugs that
treat more than one condition (e.g., beta-blockers for both
hypertension and angina pectoris) when practical.
• Discontinue drugs unnecessary in hospital, e.g. urinary
antispasmodic when catheter has been placed,

27. Safe Prescribing Habits:
When initiating a new medication:
•Choose agents whose PK properties in elderly patients are known.
•Begin with a short-acting agent but by discharge convert to an agent
that is given once or twice daily in order to enhance patient compliance
and reduce caregiver burden at home.
•If patients require multiple medications, avoid, whenever possible,
drugs that are inhibitors or inducers of Cytochrome P450 hepatic
metabolism, or are highly bound to albumin. Examples: ceftriaxone,
diazepam, lorazepam, phenytoin, valproic acid, warfarin. If in doubt,
consult a pharmacist, on-line pharmacology program, or text source.
•When the maintenance dose of a medication is not established, “start
low and go slow”, to allow time to titrate the dose against the desired
clinical effect.
•Use lower than usual maintenance doses of medications that are renal
excreted (e.g. digoxin).

28. Adverse drug events (ADE’s):
•Anytime a patient develops a new or unexplained medical
problems consider ADE as a cause: e.g. delirium,
hypotension, arrhythmias, renal failure, electrolyte
disorders, constipation.

29. At time of discharge:
• Review medications that were taken by patient
prior to admission and evaluate which should be
renewed on discharge
• Review all discharge medications with the
patient and family, and provide written
instructions.

30. General Prescribing Guidelines for the
Elderly
1. When prescribing new medications review the
following issues
– Is medication necessary? (i.e. is there a non-
phamacologic treatment?)
– Determine therapeutic endpoints
– Assess: risks vs. benefits
– Can one medication treat more than one condition?
– Administration time matches existing medicines?

31. 2. Identify all drugs by generic name and drug class
3. All drugs prescribed should have clinical indications.
4. Know the side effect profile of drugs you prescribe
5. Understand aging pharmacokinetics and how to decrease
ADE’s
6. Stop all drugs without known benefit
7. Stop all drugs without clinical indication
8. Always attempt to substitute less toxic drug
9. Avoid negative prescribing cascade (i.e. treating one
ADE with another drug)

32. 10. Brown Bag inventory (Annual or biannually)
– Request assistant go thru OTC’s, Creams and “left
over” meds. and record for you. (25 % of
prescription drugs not recorded)
– Most effective is coincides with annual major check-
ups.
– Reception staff to automatically remind patients
(when they schedule appointments for annual
exams) to bring in all medications for a “Brown Bag
inventory.”
– Offer to throw away outdated and unused meads.

33. 11. Follow these axioms:
– “ One disease, One drug, Once a day”
– “Go-Low, Go-Slow”
– (start with½ usual dose, take twice the time to
increase )
– “Fix the CAN’T’s” (read, afford, open, remember,
swallow)

34. General prescribing guidelines for
Pregnant Women

36. INTRODUCTION
• Pregnant women may require drug therapy for pre-
existing medical conditions or for problems
associated with their pregnancy.
• This patient population may be exposed to drugs or
environmental agents that have adverse effects on the
unborn .
• It is important to understand the principles of drug
use in these patients because any drug administered to
a pregnant women may directly harm the developing
fetus or adversely influence her pregnancy.
Maternal Fetal Circulation.flv

37. FETAL DEVELOPMENT: The effect of drug therapy in pregnancy
depend largely on the stage of fetal development during which
exposure occurs.
1. Blastogenesis: During this stage (the first 15-21 days after
fertilization), cleavage and germ layer formation occur.
The embryonic cells are in a relatively undifferentiated stage.
2. Organogenesis: (14-56 days) All major organs start to
develop during this period.
Exposing the embryo to certain drugs at this time may cause
major congenital malformations.
3. Fetal period: (ninth week to birth) At the ninth week, the
embryo is referred to as fetus. In this stage the developing fetus may
be at risk from exposure to the pharmacological effects of a variety of
fetotoxic drugs and microorganisms.

38. Placental Transfer Of Drugs
• The placenta is formed by the chorionic villi of the embryo and the
decidua basalis of the endometrium of the mother.
• It is the functional unit between the fetal body and the maternal
blood.
• The function of the placenta include nutrition, metabolism,
respiration, excretion and endocrine activity to maintain fetal and
maternal well being.

40. In order for a drug to cause a teratogenic or
pharmacological effect in the embryo or fetus, it must
cross from the maternal circulation to the fetal circulation
or tissues. Generally, this passage occurs via placenta.
The placenta is not a protective barrier: The transfer
of most nutrients, oxygen, waste products, drugs and
other substances occurs via passive diffusion.
Placental Transfer Of Drugs…

41. Factors affecting placental drug transfer
a. Molecular weight: Low molecular weight (less than 500 daltons)
diffuse freely across the placenta. High molecular weight drugs(500-
1000 d) cross less easily. Very large molecular wt. drugs eg.heparin
do not cross the placental membranes.
b. pH: Weakly acidic and weakly basic drugs tend to diffuse across the
placental membranes.
c. Lipid solubility: Moderately lipid-soluble drugs easily diffuse across
the placental membranes.
d. Drug absorption: During pregnancy, gastric tone and motility are
decreased, which result in delayed in delayed GI emptying time.
e. Drug distribution: The alteration of volume of distribution is the
result of a combination of changes associated with pregnancy,
including increased plasma volume and increased cardiac output
secondary to an increase in stroke volume and heart rate.

42. f. Plasma protein binding: Free unbound drug crosses
the placenta.
g. Physical characteristics of the placenta: As
pregnancy progresses, the placental membranes
become progressively thinner, resulting in a decrease
in diffusion distance.
h. Coexistent disease states: Maternal hypertension
or diabetics may reduce or enhance placental drug
transfer.
Factors affecting placental drug transfer…

43. FDA Pregnancy Category
The FDA has a categorization of drug risks to the fetus that runs
from: "Category A" (safest) to "Category X" (known danger--do
not use )
Category A
Controlled studies in women fail to demonstrate a risk to the
fetus in the first trimester (and there is no evidence of a risk in later
trimesters), and the possibility of fetal harm appears remote.
Category B
Either animal-reproduction studies have not demonstrated a fetal
risk but there are no controlled studies in pregnant women, or
animal-reproduction studies have shown an adverse effect (other
than a decrease in fertility) that was not confirmed in controlled
studies in women in the first trimester (and there is no evidence of a
risk in later trimesters).

44. Category -C
Either studies in animals have revealed adverse effects on the fetus
(teratogenic or embryocidal or other) and there are no controlled studies in
women, or studies in women and animals are not available. Drugs should be
given only if the potential benefit justifies the potential risk to the fetus.
Category -D
There is positive evidence of human fetal risk, but the benefits from
use in pregnant women may be acceptable despite the risk (e.g., if the drug
is needed in a life-threatening situation or for a serious disease for which
safer drugs cannot be used or are ineffective).
Category -X
Studies in animals or human beings have demonstrated fetal
abnormalities, or there is evidence of fetal risk based on human experience
or both, and the risk of the use of the drug in pregnant women clearly
outweighs any possible benefit. The drug is contraindicated in women who
are or may become pregnant.

45. Examples of teratogenic and potentially toxic drugs are
1) Vitamin A derivatives: Vitamin A, isotretinoin.
2) ACE inhibitors
3) Warfarin and warfarin derivatives
4) Estrogen and androgen
5) Ethanol
6) Antibiotics: e.g. Tetracycline, metronidazole, quinolone etc
7) Lithium
8) Anticonvulsants: e.g. Phenytoin, valproic acid, trimethadione and
sodium valproate.
9) Antineoplastics: e.g. Busulfan, chlorambusil, cyclophosphamide
and methotrexate.
10)Finasteride

46. • Fetotoxic drug effects are the result of pharmacological
activity of a drug that may physiologically affect the
developing fetus.
Clinically significant fetotoxic effects include the
following:
1) CNS depression: eg. Barbiturates, tranquilizers,
antidepressants, narcotics, analgesics and anesthetics.
2) Neonatal bleeding: eg. NSAIDs, anticoagulant.
3) Drug withdrawal: barbiturates, narcotics, benzodiazepines,
alcohol.
4) Reduced birth weight: Pregnant women who smokes
cigarettes, consume alcohol or abuse drugs.

47. DRUG EXCRETION IN MILK
After a drug is administered to a nursing mother, the drug may be
partially activated or inactivated in the maternal liver.
The drug may be metabolized to active or inactive metabolites.
The primary hormone responsible for controlling breast milk
production is Prolactin.
DRUGS THAT DECREASE SERUM PROLACTIN LEVELS
a) Ergot alkaloids
b) L- dopa
c) Bromocriptine
DRUGS THAT INCREASE SERUM PROLACTIN LEVELS
a) Metoclopramide b) Methyldopa c) Amphetamines d) Haloperidol
e) Phenothiazine f) Theophylline

48. EXAMPLES OF DRUGS THAT READILY ENTER BREAST
MILK:
• Narcotics, barbiturates and benzodiazepines- Hypnotic effect
on the nursing infant.
• Antidepressants and antipsychotics
• Metoclopramide- CNS effects
• Anticholinergic compounds- CNS effects

49. • Decisions relating to the use of medications can be particularly
challenging, as pregnancy or termination can have significant
effects on the woman’s mental and physical health.
• Health care professionals need reliable and up to date information
about therapeutics in pregnancy, so that they can give women good
advice to assist them in making informed choices.
• By being over-cautious effective medication may be denied with
associated risks of relapse or unwarranted termination can result.
• Being under-cautious may risk harm to babies as a consequence of
drug exposure.

50. Pharmacokinetic Changes during Pregnancy
Absorption
•Slowed gastrointestinal motility may delay absorption
of oral agents.
Renal clearance
•Glomerular filtration rates increase in pregnancy to
150% of normal range; many medications that are
renally cleared require dosage alterations in pregnancy.
For example, digoxin doses may need to be increased to
as much as 1.0 mg by the end of the second trimester.
Hepatic clearance
•An increase in hepatic clearance of pharmacologic
agents is often seen during pregnancy.

51. Volume of distribution
•Plasma volume increases to 150% of normal by 24 to 28
week’s gestation, increasing the volume of distribution.
•Drugs may require dosage adjustments.
Protein binding
•Dilution of serum proteins—caused by the increase in free
water that is responsible for most of the increase in blood
volume during pregnancy—may lead to increased free
drug levels for a particular total serum level.
Pharmacokinetic Changes during Pregnancy…

52. Practical applications
The main practical applications of the above information
are:
•Dosing intervals may need to be shortened in pregnancy.
•Inadequate dosing frequency should always be considered
as a possible cause for treatment failure.
•This is particularly true for once-a-day agents used to
control hypertension; careful examination of blood pressure
toward the end of a dosing interval may lead the clinician to
increase dosing frequency.
•Clinicians may want to monitor medication levels
periodically during pregnancy, and then adjust doses as
necessary.
•Free drug levels are better guides than are total serum
levels.

53. General Principles
• Involve prospective parents fully in the decision making process
• Treat only when necessary
• Consider risk of relapse against potential harm to fetus & mother
• Avoid all medication in first trimester when possible
• Use established drugs at minimal effective dose.
• Avoid Polypharmacy
• For some drugs there is demonstrated evidence of harm to the fetus
during pregnancy e.g. valproate
• Take account of changes in pharmacokinetics as pregnancy progresses
• Monitor neonate for adverse effects and provide feedback on outcome
• Involve other healthcare professionals to avoid giving conflicting
advice
• Document all discussions and decisions thoroughly

54. Source Type Description
Drugs in pregnancy & Lactation
A Reference guide to fetal &
neonatal risk.
Briggs CG, Freeman RK, Yaffe SJ;
5th
ed.
Hardcover
reference text
Comprehensive evaluation by a panel of
experts on all available data.
Excellent reference. Provides specific
judgments regarding use of each agent in
pregnancy & lactation.
Handbook for prescribing
medication during pregnancy
Coustan DR, Mochizuki TK, 3rd
ed.
Pocket size
paperback
reference text
Convenient format with reliable
information. Referencing is less extensive
than in other sources
The effect of drugs on the fetus
& Nursing Infants: A Handbook
for healthcare Professionals.
Friedman JM, Polifka JE
Paperback
reference text
Succinct summarizes of risk based on
more comprehensive reviews in TERIS.
An excellent & affordable resource.
Provides specific comments on both
estimate of safety risk & quality of data
on which that estimate is based.
Motherisk
http://www.motherisk.org.
Website Excellent information on common clinical
questions with a thorough bibliography.
Catalogue of teratogenic Agents
Shepard TH; 9th
ed.
Hardcover
reference text
Excellent summary of available data with
respect to teratogenesis, but it does not
provide clinical judgments about
appropriateness of use in pregnancy and
does not address lactation.

55. Source Type Description
FDA pregnancy risk
categories
Found in most package
inserts or on labels.
Medication
labels
Well known categories: A, B, C, D & X
Reprtotox
http://www.REPROTOX.org
; also available on a disk
distributed as part of
Micromedix’s TOMES
Reprorisk module.
Online
subscriptio
n or
diskette
Comprehensive evaluation of available
human & animal data on environmental
hazards & medications. All aspects of
human reproduction are considered.
Similar to TERIS (see below), although
there is less directive in linking risk to
management. Frequently updated.
Extensive references provided
TERIS
http://weber.u.washington.ed
u/-terisweb/teris or on a disk
distributed as part of
Micromedix’s TOMES
Reprorisk module
Online
subscriptio
n or
diskette
Comprehensive evaluations of available
human and animal data on individual
drugs by a panel of experts. Excellent
reference. Provides specific judgments—
with rationale—of risk in pregnancy and
lactation.